Bushfire Fuel Classification Overview

BUSHFIRE FUEL CLASSIFICATION OVERVIEW

2|B USHFIRE FUEL CLASSIFICATION

OVERVIEW

WHAT IS THE BUSHFIRE FUEL CLASSIFICATION? For millennia, fire has played an important role in shaping Australian environments with deep implications for bushfire management and prescribed burning. The rich and diverse vegetation present in Australia results in a multitude of fuel types with distinct fuel arrangements, quantities and combustion characteristics. A fuel classification aims to integrate vegetation diversity into a few differentiable fuel types that are easily communicated and quantitatively described (Keane 2015).

Australian land and fire managers have recognised the need for a national-level fuel classification to provide a consistent method of characterising and categorising fuels to support a wide range of fire management activities such as assessment of fuels, assessment of bushfire risk, planning landscape fuel management, sharing fire behaviour analysts and predicting the behaviour and growth of fires.

The Bushfire Fuel Classification (BFC) provides a guideline for a standard classification of fuels in the Australian landscapes, and will be supported by a range of products as shown below:

POSITION

APPROACH

BFC OVERVIEW (THIS DOCUMENT)

THE BUSHFIRE FUEL CLASSIFICATION

GLOSSARY OF TERMS

TOOLS

SPECIFICATIONS FOR THE BFC

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WHAT IS THE PURPOSE OF THE BFC? The purpose of the BFC is: To facilitate effective bushfire management by providing a nationally consistent classification of bushfire fuel to improve communication, cross-border interoperability and facilitate the use and development of bushfire management support tools, especially fire behaviour predictive tools.

HOW DID THE BFC COME ABOUT?

WHAT ARE THE BENEFITS?

The BFC emerged from extensive consultation with land managers and rural fire authorities, and a review of other classification systems used throughout the world.

The Australasian Fire and Emergency Service Authorities Council (AFAC) and the Forest Fire Management Group (FFMG) commissioned the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to investigate the potential for a national fuel classification. In a previous report Development of a Framework for a Bushfire Fuel Classification (Hollis et al.

2014), CSIRO investigated a potential framework for a fuel classification, to meet the desired uses for a fuel classification as expressed by state government agencies and to address the requirements of fire behaviour models and fire growth simulators. The report reviewed existing international fuel classification systems and finally, proposed a framework for classifying fuels in Australia.

• Improved cross-border operations especially with regard to common understanding around fuel type descriptions, fuel dynamics, fire behaviour predictions, hazard and risk assessments and suppression difficulty; • Supporting national rollout of fire behaviour predictive services and the new national fire danger rating system; • Improved cross-border communication and interoperability in relation to fuel assessment; • Supporting utilisation of a range of fire management support tools; • Providing a nationally consistent approach for fuel classification, terminology and best practice for fuel appraisal; • Fostering the development of nationally applicable tools and research based on the BFC standard; • Providing state agencies a means to convert their vegetation data or mapping into the BFC fuel standard; • Providing nationally consistent inputs into a range of processes including local government or landscape planning and other projects attempting to build consistency or standards; • Providing improved and more consistent inputs for prescribed burn planning, risk and hazard assessments, evidence-based decision making and for evaluation, monitoring and reporting processes; and • Improved basis for public information, engagement and education.

4 | BUSHFIRE FUEL CLASSIFICATION

OVERVIEW

HOW DOES THE BFC WORK?

The BFC includes two main components: Categorising fuel – a hierarchical approach to identifying fuel types. This is achieved by using a three tier coding system.

CATEGORISING FUEL The BFC uses a hierarchical approach to classify fuels (by using tiers). There are three tiers plus an optional layer of fuel description: - The top tier organises the diversity of vegetation types found across Australia into a standardised set of broad fuel types based on the structural properties of the canopy (using structural categories derived from Specht 1970, which are already in wide use); - The mid tier refines these fuel types by identifying the major fuel layers, including understorey fuels, that have a large influence on combustion and fire propagation processes; - Below the mid tier, the bottom tier provides a current description of fuel accumulation as determined by time since fire and by environmental and climatic influences; and - The BFC includes an optional customised description nested within the BFC bottom tier that allows a user-defined fuel description to support situations where the user has detailed sampling data.

Describing the fuel within fuel types – This is achieved by populating a fuel catalogue that records fuel characteristics.

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An illustration of the categorising tier system is provided below (with example fuel types included):

VEGETATION DESCRIPTION e.g. EVC, NVIS

Top Tier OPEN FOREST FM3

Mid Tier

OPEN FOREST WITH SPARSE COVER OF LEAF LITTER

OPEN FOREST WITH CLOSED COVER OF LOW GRASSES

FM3_l1

Bottom Tier (under development)

OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS

FM3_gl4

OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 0-3 YEARS SINCE FIRE

FM3_sm3

OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 4-7 YEARS SINCE FIRE

FM3_sm3_1

Custom Fuel Complex (under development)

OPEN FOREST WITH DENSE COVER OF TALL SHRUBS

OPEN FOREST OF MEDIUM SHRUBS 5 YEARS OLD MCCORKHILL BLOCK

FM3_st4

OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 8-11 YEARS SINCE FIRE

FM3_sm3_2

FM3_sm3_3

OPEN FOREST OF MEDIUM SHRUBS 7 YEARS OLD MCCORKHILL BLOCK

DESCRIBING THE FUEL WITHIN FUEL TYPES The fuel types defined within the tier system are accompanied by a description of their characteristics (such as fuel load, fuel hazard, shrub layer height etc.). There is a list of recommended fuel characteristics; however, exactly which characteristics are to be recorded is selected at the discretion of BFC users according to their needs.

The top tier will include wide data ranges for each characteristic (e.g. fuel load = 4 to 8 tonnes/ha with a mean value of 6 tonnes/ha), with that data range becoming narrower at lower tiers. The mean value is provided to enable practical applications. Each tier can support a full description of fuel characteristics, however the lower the tier, the more precise and meaningful the description.

The BFC acknowledges that new fuel characteristics may be required in the future as a result of a better understanding of the effect of the physical properties of fuel on fire behaviour. As such the list of fuel characteristics is expected to expand over time.

Fuel characteristics can be recorded in a fuel catalogue which can support the development of a range of fire management tools such as: • Input into fire behaviour models and fire growth simulators; • The development of photographic fuel assessment field guides or apps; and • Input into future fire danger rating systems.

6 | BUSHFIRE FUEL CLASSIFICATION

OVERVIEW

Table 1 The Bushfire Fuel Classification top and mid tier fuel types Version 1 (19-11-2015)

Australian Bushfire Fuel Classification – Top and Mid Tier Cover Class

1 (1-5%)

Growth Form

Top Tier - Name

2 (5-30%) Code

Mid-Tier

Trees >30m

3 (30-70%)

Top Tier - Name

Code

Mid-Tier

Top Tier - Name

Tall Woodland

WT2

st

Tall Open Forest

g Trees 10-30m

Woodland

WM2

hg

Open Forest

gt gl st sl Trees <10m

Low Woodland

WL2

gt

Low Open Forest

gl st sl hg Shrubs 2-5m

Tall Open Shrubland

ST2

hg

Tall Shrubland

g sm Shrubs <2m

Low Sparse Shrubland

SL1

hg

Low Open Shrubland

SL2

g

hg

Low Shrubland

g sm

Hummock grassland

Sparse Hummock Grassland

HG1

Hummock Grassland

HG2

Dense Hummock Grassland

Grassland

Sparse Grassland

G1

Open Grassland

G2

Grassland

A standardised naming and coding convention has been developed based on the three tier structure. It consists of: • Standardised codes; • Standardised descriptive names; and • Additional fuel type codes outside the native vegetation structural form groups (e.g. plantations, the wildland-urban interface, horticultural and activity fuels such as logging and pruning slash).

The coding has 3 separate fields AA#_aa#_#. The first field (AA#) describes the top tier, the second field (aa#) describes the mid tier and the third field (#) describes the bottom tier.

Extra supplementary codes identifying rainforest vegetation and bark status can be added.

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4 (>70%)

OTHER

Code

Mid-Tier

Top Tier - Name

Code

FT3

st

Tall Closed Forest

FT4 (R)

Mid-Tier

Top Tier - Name

Code

Conifer Plantation

PC

Mid-Tier PRAD

fl

PSOU PPIN

FM3

lit

Closed Forest

FM4 (R)

PARA

gt

Broadleaf plantation

PB

PESR

gl

PEMR

st

Wildland Urban Interface WUI1 (< 0.1 house per ha)

sl FL3

gt

WUI2 (0.1 ≤ houses per ha ≤ 1) Low Closed Forest

FL4 (R)

WUI3 (>1 houses per ha)

gl

Wetland

st sl ST3

hg

Tall Closed Shrubland

ST4

sm SL/M3*

g

WET1 (permanent wetlands) WET2 (combustible wetlands)

Low Closed Shrubland

SL/M4*

Horticultural

HOR

Activity Fuels

AF

Other Fuel Types

TBC

Non-combustible

NB

*Mid Tier Types

SL – Short < 0.5m SM – Medium 0.5-2m

HG3

G3^

1

Closed Grassland

G4^

1

^ Mid Tier Types

1 – Eaten Out

2

2

2 – Grazed or cut

3

3

3 – Ungrazed or natural

TOP TIER CODE

MID TIER CODE

F W P S HG G

s hg g f lit

Forest Woodland Plantation Shrubland Hummock Grassland Grassland

HEIGHT CODE (TOP/MID TIER)

T/t tall (trees >30m, shrubs 2-5m,

grasses >1m) M/m medium (trees 10-30m, shrubs 1-2m) L/l (trees <10m, shrubs <1m, grasses <1m) FOLIAGE COVER CODE (TOP AND MID TIER)

1 2 3 4

less than 5% (very sparse) between 5-30% (sparse) between 30-70% (open) greater than 70% (closed)

AA#_aa#_#

shrubs hummock grasses grasses ferns litter

BOTTOM TIER CODE

Yet to be defined SUPPLEMENTARY CODES (TOP TIER)

R

Rainforest

SUPPLEMENTARY CODES (MID TIER)

B Br Bf

Bark Ribbon Bark Fibrous Bark

WHERE TO FROM HERE? The BFC has been adopted in principle by the AFAC Council and a supported program to help agencies convert data to the new standard will be rolled out beginning 2016.

For further information about the BFC contact AFAC on (03) 9419 2388.

REFERENCES Hollis JJ, Gould JG, Cruz MG, Doherty M (2014) Development of a framework for a Bushfire Fuel Classification (CSIRO: Canberra) and (AFAC: Melbourne) – available from the AFAC shop at www.afac.com.au Keane RE (2015) Wildlands fuels fundamentals and applications.

(Springer International Publishing: Switzerland) Specht RL (1970) Vegetation. In ‘Australian Environment’ 4th edition (ed. Leeper GW). (Melbourne University Press: Melbourne) pp. 44–67 Photos in this document were provided courtesy of: CSIRO, Office of Bushfire Risk Management Western Australia, The Bushfire CRC, Parks and Wildlife Service Tasmania and David Taylor.

Level 1, 340 Albert Street, East Melbourne, Victoria, Australia, 3002 T +61 3 9419 2388 | F +61 3 9419 2389 E afac@afac.com.au www.afac.com.au

The Bushfire Fuel Classification is part of the National Burning Project (NBP). The NBP is building frameworks and national guidance relating to prescribed burning.

Products are available at: www.afac.com.au/initiative/burning